UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players

Notices

Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players Open-reel tape recorders, cassette recorders, 8-track players etc.

Closed Thread
 
Thread Tools
Old 26th Jul 2012, 10:52 pm   #1
jodal666
Retired Dormant Member
 
Join Date: Jul 2012
Location: Chingford, London
Posts: 8
Default Studer B67 Problems... Help

Hi all,

First Post here, so hello to everyone.

I have acquired various Studer R2R machines which been in a basement for approx 15 years.
The first one I'm having a problem with is a B67 Mk2 (B67-2-2.00 MK2) The tape path was cleaned prior to use and all is in very good order .

When powered for the first time the unit played back tape through the onboard monitor speaker. The next day there was no output from the speaker, although there is a slight hum from the speaker at full volume. Other transport control functions seem work correctly.

I've been looking through the service manual to check the supply voltages to the plug-in boards connected to the basis board. The -12v is present at the board but it doesn't get to the plug-in cards (Pin14?) connected to the basis board. All other supply voltages seem to be present 5V, 12V, 0V on the plug-in cards.

I've tried to follow the PCB track, but I cannot see where the track should go. Any Ideas? My eyes are starting to go fuzzy looking at all the green PCB track.

Regards,

Jodal666

Last edited by Darren-UK; 26th Jul 2012 at 11:25 pm. Reason: Format.
jodal666 is offline  
Old 27th Jul 2012, 12:49 am   #2
Michael Maurice
Moderator
 
Michael Maurice's Avatar
 
Join Date: Feb 2006
Location: Wembley, Middlesex
Posts: 7,219
Default Re: Studer B67 Problems... Help

Do you have the service manual for this machine?

If not then you need to get one, preferably in paper form.
__________________
Forum Moderator

http://www.michaelmauricerepairs.co.uk/
Michael Maurice is offline  
Old 27th Jul 2012, 8:34 am   #3
jodal666
Retired Dormant Member
 
Join Date: Jul 2012
Location: Chingford, London
Posts: 8
Default Re: Studer B67 Problems... Help

Hi,

I have the electronic PDF Service manual Studer Mk1 and 2 but can't print it.
Voltage supplies are leaving the interconnection PCB board 1.167.750 plug EL3. pins 13-20 voltages are OK. If I remove EL3 plug from interconnection board, the supply voltages disappear from the basis board as expected.

One thing I have noted, some of the voltages from the PSU are a little out of spec. +26.3v on the +24v rail, +21v on the +20v rail. Potential capacitor problems?

I haven't done much electronics servicing to component level for quite a few years, 20+. but it's coming back, slowly.

Test equipment:
Dual channel oscilliscope, old but working ok. 25Mhz
Signal generator (ramp, sine, square),
DVM.
Soldering station.
Fostex TT-15 tone gen 40Hz, 100Hz, 1KHz, 10KHz, 15KHz
Tape BASF SM468.PER 368, Zonal 810
The Ampex 457 was suffering badly from binding. Sticky shed syndrome. I think that's what you call it.

I like a challenge! I couldn't see them thrown in a skip. I had to rescue them.

Regards,

Jodal666
jodal666 is offline  
Old 27th Jul 2012, 10:47 am   #4
Michael Maurice
Moderator
 
Michael Maurice's Avatar
 
Join Date: Feb 2006
Location: Wembley, Middlesex
Posts: 7,219
Default Re: Studer B67 Problems... Help

Small differences on the 24V line 20V line can be expected, the +12V - 12V and 5V should be spot on.

If you've got the manual then I'm afraid its down to checking with a meter until you find the broken print.

The fact that the transport system is working means that the supplies are all up and running.
__________________
Forum Moderator

http://www.michaelmauricerepairs.co.uk/
Michael Maurice is offline  
Old 27th Jul 2012, 12:15 pm   #5
jodal666
Retired Dormant Member
 
Join Date: Jul 2012
Location: Chingford, London
Posts: 8
Default Re: Studer B67 Problems... Help

Hi Michael,

I need to get some pinch rollers, some of the old ones had dissolved:

B67mk1 x 1
PR99 x 1
B77 x 2

Counter belts: B77

Are there any sources in the UK? There is a guy who has spares in Germany.

pics
http://s10.photobucket.com/albums/a1...l%20to%20Reel/

Regards,
Jodal666
jodal666 is offline  
Old 27th Jul 2012, 12:50 pm   #6
djwells01
Triode
 
Join Date: Jun 2010
Location: Norwich, Norfolk, UK.
Posts: 22
Default Re: Studer B67 Problems... Help

Hi jodal666,

If I remember correctly the pinch rollers for B67/PR99/B77 are interchangeable, the following may be able to help in the UK.

Nigel Hunt - http://www.taperecorder.co.uk

Brian Reeves - http://www.revox.freeuk.com/

Hope that helps.

Duncan

Last edited by Michael Maurice; 27th Jul 2012 at 3:14 pm. Reason: correction to 1st website
djwells01 is offline  
Old 27th Jul 2012, 2:22 pm   #7
jodal666
Retired Dormant Member
 
Join Date: Jul 2012
Location: Chingford, London
Posts: 8
Default Re: Studer B67 Problems... Help

Duncan,
Many thanks for the info. I'll get some ordered.

I did try one of the B77 pinch rollers on the B67 and seem to be an exact fit. The only thing that seemed different was the rubber colour. The B67 mk1's are green colour. The B67 mk2 is black. seems to work ok.

Still trying to track down the missing -12v supply on the basis board. missing from pin14 on all plugin cards

Annotated PCB drawing attached.

Regards,
Jodal666
Attached Thumbnails
Click image for larger version

Name:	Basisboardwithannotation.jpg
Views:	116
Size:	120.6 KB
ID:	69078  
jodal666 is offline  
Old 28th Jul 2012, 4:56 pm   #8
Michael Maurice
Moderator
 
Michael Maurice's Avatar
 
Join Date: Feb 2006
Location: Wembley, Middlesex
Posts: 7,219
Default Re: Studer B67 Problems... Help

The +12V and -12V are derived from the stabiliser card and this in turn from the +20V and -20V from the power supply.

I suggest you check whether you get -20V on pin 4 of the stabiliser card. If you do but dont get -12V on pin 14 then your fault is with the stabiliser card.

It might be an idea to do a cold check (power off) between pin 14 and ground, to make sure there are no short circuits.

See diagrams below.
Attached Thumbnails
Click image for larger version

Name:	Basisboardwithannotation.jpg
Views:	140
Size:	62.7 KB
ID:	69119   Click image for larger version

Name:	stabiliser.jpg
Views:	162
Size:	54.6 KB
ID:	69120  
__________________
Forum Moderator

http://www.michaelmauricerepairs.co.uk/
Michael Maurice is offline  
Old 28th Jul 2012, 5:47 pm   #9
jodal666
Retired Dormant Member
 
Join Date: Jul 2012
Location: Chingford, London
Posts: 8
Default Re: Studer B67 Problems... Help

Cheers, I'll check this Monday morning.
jodal666 is offline  
Old 30th Jul 2012, 3:57 pm   #10
jodal666
Retired Dormant Member
 
Join Date: Jul 2012
Location: Chingford, London
Posts: 8
Default Re: Studer B67 Problems... Help

Michael
Yes, you were absolutely right.
Short on Stabilizer PCB between Tp1 -12v and 0v
c6 47uf Tantalum Short..

now have audio on P/B

Now ordering all the caps for there machines.
X2 suppression, Electrolytic and tantalum,



John
jodal666 is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 3:16 pm.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.